Luminescent tube



a high frequency electric field.

Patented D c. 26, 1939 LPATENT time:

LUMINESCENT TUBE Harold D.

Penney, Pelham, and William Weir,

Hcunt Vernon, N. Y.

Application February 2s. rest, serial No. male s Claims. 'wi'.'1'zs-i zi) M This invention relates to luminescent tubes or envelopes and more particularly to tubes of transparent-- dielectric material having therein gas, vapor, or mixture adapted to luminesce One object of the inventionfis to provide an improved tube of this mad which is free of elec-' trodes within the interior of the tube.

Other objects of the invention are to provide an improved device of this find-which is easily arrangedand interchanged in electric signs.

Additional objects of the invention are to im-' prove generally the simplicity, efllciency and safety of such tubes and apparatus and to provide an extremely simple device or apparatus of this find which is economical, durable, safe and reliable in operation, and economical to manue facture and install.

Still other objects of the invention will appear as the description proceeds: and while herein details of the invention are described in the specification and some of the claims, the inven tion is. not limited to. these, since many and various changes may be made without departing from the scope of the invention as claimed in the broader. claims.

The inventive features for .the "accomplishment of these and other objects are shown herein in connection with several devices, each of which briefly stated, includes a dielectric envelope filled with luminescent gas and free of interior electrodes, and spaced condenser members disposed adjacent to said envelope and connected respectively to poles of a source of high frequency current, thereby to charge said members and induce a high frequency charge within the envelope inthe portions of gas adjacent. .to said members, thereby to set -.up a high frequency fieldin the gas between said portions to cause luminescence.

In the accompanying drawing showing, by way of example, several of many possible embodiments of the invention, 7

Fig. 1 is a partly diagrammatic front elevation showing one form of the invention;

Fig. 2 is an edge elevation showing details oi.

Fig. 6 is a front elevation showing one form" of the envelope or tube:v

, Fig. 8;

Fig. '8 is a plan showing the tube of Fig. 8; Fig. Bis a front elevation showing the envelope or tube with metal end caps;

Fig. 9 is an'edge elevation showing the tube of 5- Fig. 10 is an enlarged sectional view taken on the line i0-I0 of Fig. 8; Fig. ii is an enlarged transverse section taken intermediately'of another form of tube;

. i2 is a perspective of one form of tube 10 shown in place on a board with a different ary Fig. 14 is a diagram showing the electrical l5 relation between the parts of the tube of Fig. 13.

A simplified form of my invention will first be explained, after which special adaptations will be described. Referring to Fig. 13, there is shown a transparent dielectric envelope or tube 5 free oi interlor electrodes and filled throughout with a rarefied gas 6,. I, 8 adapted to luminesce in a high frequency oscillatory electric field. Upon the ends of the tube 5 are disposed electrically conducting metal members or caps 9, l0 respectively electrically connected by conductors II, l2 to the respective poles'of a high frequency electric current source.

This forms an oscillatory system similar in form to that shown in Fig. 14 which comprises an inductance 8 connected between elements or -members I, 8 of a, pairof condensers I, 9' .and 8', l0 comprising outer elements or members 9', l0 adapted respectively to be connected by conductors Hf, W to the poles of the high in the respectively adjacent portions], 8 of gas just inside the tube which layers I, 8 become con- 4 denser-elements respectively corresponding to the members I, 8 of Fig. 14, and the intermediate gas I in the tube becomes an inductance correspending to theinductance 6'.

Thus the intermediate gas becomes an inductance in a high frequency system, and the oscillatory electric field therein causes the gas 'to luminesce. r

' This electric field is concentrated exactly where it is most needed to eflect the luminescence, '55

and the system is much more eflicient than those wherein a coil surrounds a large envelope. Also the system is more efliclent than those having within the tubes, electrodes which get very hot; while herein, the caps l, 8, being exterior to the tube dissipate the heat very easily and do not get excessively warm.

Any suitable or well known gas or mixture may be used within the envelope; but the system' is particularly useful for producing ultra-violet rays, in which case a quartz tube having therein argon, neon and mercury gives excellent results.

Fig. 1 shows a diagrammatic view of a practical embodiment of the invention in the form of a sign having luminescent letters l5.

Any suitable source of high frequency current may be used, but here it is shown as including a transformer primary i6 adapted to be connected between the terminals ll of a 1l0-volt source of alternating current, and a secondary l8 wound to give, for example, a voltage of 3000 to 7000 volts. Spark-gap means connected between the terminals of the secondary comprises a series of closely spaced insulated sparking blocks 2i.

A pair of conductors are electrically connected to and extend from the ends of said spark gap means, providing a source of high frequency alternating current of, for example, about 10,000 to 3,000,000 cycles.

The sign of Fig. 1 includes an insulating board 27 of artificial resin, porcelain or other insulating material between opposite faces of which -near opposite margins of the board conductors,

rods or wires 28, 29 connected to the respective, conductors 25 are received, cast in or otherwise disposed in the board. 'A pair of groups of parallel strips or bars 30, 3| of thin copper, metal foil or other conducting material are cemented to, or seated or cast in, a surface of said board 2? transverse to said conductors.

The bars of one group 30 alternate with bars of the other group 3|, adjacent ends of the bars of each group project beyond the adjacent end of the other group, as shown, and are downturned as at 33 into the interior of the board, to form two series of connecting ends adjacent to apposite edges of the board respectively, the downturned ends of the bars 30 being electrically connected to said conductor 28, while the down-- turned ends of the bars 3| are connected to conductor 29.

High frequency oscillating charges are charged into and discharged from said bars 30, 3 I thereby inducing a high frequency oscillating electric field.

The letters It comprise electrodeless luminescent members or glow tubes of letter or other shape disposable in said electric field flatly ad= iacent to or against said board and bars and each having, a rounded exposed side 35, (Fig. 11)

and a fiat side 36 disposable against said bars 30, 3|, each tube comprising a completely closed envelope of glass or other suitable transparent material filled with neon or other suitable gas vapor or mixture adapted to luminesce when disposed in said field.

If desired, flange plates 38 are secured to the top and bottom edge faces of said board 21 and formed with inner flanges 39 spaced from the board to engage over the luminescent members I! to hold them on the board and allow their removal by sliding to the ends of said plates. If desired, the uppermost flange 38 may be wider, and the distances between the flange plates il may be slightly greater than the length of the letters,to permit the lower end of the ietter to be removed from behind the lowerflange, while the upper end is still behind the flange, thus to allow easy removal of an intermediate letter without disturbing others.

The bars 30, 3| may be horizontal as in Fig. 1 or they may be vertical, as are the bars 30', 3| seated in the board 21' of Fig. 12.

Also metallic sheet or foil caps 39', 40 or other conductors may be provided on the ends or sides of said envelopes or tubes i5, as in Fig. 9 to be engageable with said bars 30, 3! or 30', 3! to receive high frequency charges therefrom, thereby to increase the high frequency fields in the tubes, to increase the luminescence.

In the form of invention of Fig. 11, separate metallic members 301; may be disposed against the back of the tube. These may be secured to the board as are the members 30 or they may be secured to the back of the tube itself at spaced areas thereof and engaged with the bars 30, 3| or otherwise connected by conductors to the current source.

In the form of invention of Fig. 1, the bars 30, 3! correspond to the members 9, l0, 9', ill of Figs. 13 and 14, and the adjacent gas just within the conductor corresponds to the gas at l and 8 of Fig. 13 or the elements 1', I0 of Fig. 14, and the high frequency charges induced in the bars 30, 3|, in'like manner set up an oscillatory electric field in the tube l5, which causes luminescence therein. In like manner the strips 30', 3|, 30a and the caps39', 69 correspond to the members 9, i0, 9', l0.

In order to avoid danger of shocks, as from the high voltage bars 80, ii, I provide the arrangement of Figs. 4 and 5. Here the letters are supported on a hollow support 41 of dielectric material having longitudinal slots 48 establishing communication from exterior to interior of the support, adiacentato which slots are spring clips 48, 49 of conducting material secured on the inner face of the support on opposite sides of each slot. Conductors 25 connect the clips 48 of the two slots with the poles of said high frequency source respectively; and the envelopes 45 of transparent dielectric material placed on the support and each have a pair of extensions 50 disposed in the respective slots and engaging adjacent clips 48, 49. In this case the clips 48 correspond to the members 8, I 0 of Fig. 13, and when they are charged with the high frequency charges, gas in the ends 50 corresponds to the gas at 1 and 8 of Fig. 13, and a high frequency field, and consequent luminescence are set up in the tube 45, the exposed part on the exterior of the support 01 being visible and forming the letters of the sign.

We claim as our invention:

1. In combination, a pair of conductors; an insulating board between opposite faces of which near opposite margins of the board the respective conductors are received; a pair of groups of parallel bars of thin metal seated on a surface of said board transverse to said conductors; the bars of each group alternating with bars of the other group; adjacent ends of the bars of each group projecting beyond the adjacent end of the other group and being downturned into the interior of the board, to form two series of connecting ends adjacent to opposite edges of the board respectively and connected to said conductors resp ctively.

2. In combination a source of high frequency high voltage electric current; supporting means of dielectric material; spaced members of electric conducting metal disposed on the front of supporting means and having wide front faces electrically connected to the respective poles of said source; and a plurality of luminescent glow tubes of letter shape disposable in various lotion and the luminosity of the vapor or mixture.

3. In combination a source ofhigh frequency high voltage electric current; a fiat support of,

dielectric-material; spaced strips of electric conducting metal disposed fiat on said support and connected to the respective poles of said source; and a plurality of thin electrodeless luminescent glow tubes of letter shape disposable in various locations flatly against said strips, each having a rounded exposed front side and a flat rear side against said strips, each tube comprising a complete envelope of transparent dielectric material filled with gas vapor or mixture adapted to inminesce; the flatness and thinness'of said rear side disposing said vapor or mixture close to the said strips, thereby increasing the efficiency of the combination and the luminosity of the vapor or mixture.

locations in direct contact against the front face of said members, each tube comprising a complete envelope of transparent dielectric material filled with gas vapor or ure adapted to luminesce; the directness of said contact and the thinness of said tube disposing said vapor or mixture close to the said members, thereby increasing the eficiency of the combination and the luminosity of'the vapor or mixture. I

5. In combination, a source of high frequency high voltage electric current; including a support a plurality of groups of spaced strips of electric conducting metal mounted on said support, the strips of the groups alternating, the groups being connected to the respective poles of said source to form a high frequency field; and a transparent dielectric envelope adjacent to said strips and filled with a gas adapted to luminesce in said field; said envelopes being letter shaped and extended to opposite edges of the support, the combination including flange plates secured-to the top and bottom edge faces.

and allow their-removal by sliding to the ends of said support.

6. In combination, a source of high frequency high voltage electric current; a support; a plurality of groups of spaced conductors on said support, the conductors of the groups alternating, the groups being connected to the respective poles of said source to form high frequency field; transparent dielectric letter-shaped envelopes adjacent to said strips and filled with a gas adapted to luminesce in said field; and

spaced upper and lower flange plates secured to said support and formed with inner flanges to engage over the envelopes to hold them on the support.

7. In combination, a source .parent dielectric material filled with gas vapor I or mixture adapted to luminesce; the flatness and thinness of said rear side disposing a large flat area of said vapor or mixture very close to said strips and the electric field thereof, said close flat area, extending entirely across each tube entirely from side to side of the tube, thereby causing maximum effect of said field on the .vapor at the side edge of the wide flap portion of the tube, thereby extending the maximum effectof said field at said close area entirely acrossbenign frequencyhigh voltage electric current; a fiat support of dielectric material; spaced strips of electric conthe tube from side edge to side edge thereof,

thereby increasing the efflciency of the combination and the luminosity of the vapor or mixture.

8. A group of thin electrodeless capless luminescent glow tubes of letter shape disposable in various locations flatly against spaced strips of electric conducting metal disposed flat on a flat support of dielectric material and connected to the respective poles of a source of high frequency high voltage electric current; each tube having a rounded exposed front side and a flat rear side disposed fiat against said strips, each tube comprising a complete envelope of transparent dielectric material filled with gas vapor or mixture adapted to luminesce; the flatness and thinness I of said rear side disposing a large flat area of i said vapor or mixture very close to said strips and the electric field thereof, saidclose flat area extending entirely across each tube entirely from side to side of the tube, thereby causing maximum effect of said field on the vapor at the side edge of the flat portion of the tube, thereby extending the maximum effect of said field at said close area entirely across the tube from side edge to side edge thereof, thereby increasing the efficiency of the combination and the luminosity of thevaporor mixture. I

" HAROLD D. PENNEY. 

